In the steps of manufacturing toner for image forming devices such as electrophotographic devices, waste toner (fine particles) which has substandard particle size and hence cannot be shipped as products is spun off during an eventual classification step. Even though a part of the waste toner has been recycled by being added to proper toner in the manufacturing step, there is a certain limit to the amount of the waste toner to be recycled, and the residual waste toner has mostly been treated as industrial waste.
However, since it is costly to treat waste toner as industrial waste, there has been demand for a method to effectively recycle waste toner.
As an example of such a method to recycle waste toner, Japanese Laid-Open Patent Application No. 5-317831/1992 (Tokukaihei 5-317831; published on May 15, 1992) discloses that particles of industrial waste are converted to an aggregate and into this aggregate waste toner chiefly made of thermoplastic resin is mixed as a bonding agent, thereby thermo-forming the aggregate.
As another example, Japanese Laid-Open Patent Application No. 2001-179740 (Tokukai 2001-179740; published on Jul. 3, 2001) discloses a method to obtain a molding product by fusing and kneading a used toner cartridge in which toner remains, and then molding the fused and kneaded cartridge.
As a further example, Japanese Laid-Open Patent Application No. 2001-205748 (Tokukai 2001-205748; published on Jul. 31, 2001) discloses a method for manufacturing a molding product in which waste toner as a core layer is covered with a surface skin by means of a sandwich construction method.
However, since the method of Japanese Laid-Open Patent Application No. 5-317831 utilizes waste toner as a bonding agent for an aggregate made of particles of industrial waste, certain limitations are set on (i) the application of the molding product due to the reasons such as its physical properties, (ii) the amount of the waste toner to be used, and (iii) the rate of recycling the waste toner, therefore it is not possible to effectively recycle the waste toner. Meanwhile, the method of Japanese Laid-Open Patent Application No. 2001-179740 is a method for recycling toner cartridges, rather than a method to effectively recycle waste toner which cannot be shipped as products due to substandard particle size, etc.
Moreover, neither one of the molding products obtained by the methods of Japanese Laid-Open Patent Applications No. 5-317831, No. 2001-179740, and No. 2001-205748 has sufficient physical properties such as flexural rigidity, flexural strength, and tensile strength, and thus these molding products have only limited uses.